Quasi Three Dimensional Parabolic Equation Method For Prediction Of Radio Wave Propagation

At present,the parabolic equation(PE)formula calculation method has been widely used,because it can not only describe the effects of irregular terrain structure,inhomogeneous media of atmosphere on wave propagation,the method does not depend on the wavelength,and the calculation efficiency is high.In this paper,Based on the study of two-dimensional parabolic equation(2DPE),a quasi three-dimensional parabolic equation(Quasi-3DPE)method is proposed to predict the propagation characteristics of radio waves in three-dimensional space.Firstly,the form of 2DPE is deduced in Cartesian coordinate system detailedly.The Pseudo differential operator is handled approximatively by four methods,and used the Feit-Flect method with the propagation angle up to 30 degrees to deal with the PE approximated approximatively.In this algorithm,the boundary and initial conditions that need to be considered in the process of solving the algorithm are given with the theoretical knowledge and examples of calculation.Secondly,we establish the terrain masking model to deal with boundary of irregular terrain and use the split step Fourier parabolic equation(SSFT)to calculate the wave propagation problems on the terrain in two-dimensional space,which can predict the long distance of irregular wave propagation properties of the terrain.The calculation results verify the propagation characteristics of radio waves in irregular terrain.Thirdly,on the basis of SSFT method to predict the propagation characteristics of two-dimensional spatial radio waves,a Quasi-3DPE method is proposed to predict the propagation characteristics of three-dimensional spatial radio waves.The cone as an example,from the view point,the conical can be seen as two dimensional graphics,namely the triangle(vertical plane)and circular(horizontal surface at the height of the emission source),then calculate the propagation characteristics of the two plane respectively.Adding the field values of two planes at the same propagation distance and the same height,and then calculating the corresponding propagation factor,that is the Quasi-3DPE result of the cone.Finally,the wave propagation characteristics of waves in complex atmospheric structure under the conditions of troposphere.Combined with the PE method for processing atmospheric structure complex,and the results verify the correctness of the theory through an example calculation.